MIPS: mm: Don't do MTHC0 if XPA not present
authorJames Hogan <james.hogan@imgtec.com>
Tue, 19 Apr 2016 08:25:10 +0000 (09:25 +0100)
committerRalf Baechle <ralf@linux-mips.org>
Fri, 13 May 2016 13:30:25 +0000 (15:30 +0200)
commit4b6f99d307ed6c7a28b952bfb7b66fb26a6a4cf0
treeb3a82750ade7072f1c688d8232678ef51521adbb
parent2caa89b49b21737b2b7b6fce37cb323535188b06
MIPS: mm: Don't do MTHC0 if XPA not present

Performing an MTHC0 instruction without XPA being present will trigger a
reserved instruction exception, therefore conditionalise the use of this
instruction when building TLB handlers (build_update_entries()), and in
__update_tlb().

This allows an XPA kernel to run on non XPA hardware without that
instruction implemented, just like it can run on XPA capable hardware
without XPA in use (with the noxpa kernel argument) or with XPA not
configured in hardware.

[paul.burton@imgtec.com:
  - Rebase atop other TLB work.
  - Add "mm" to subject.
  - Handle the __kmap_pgprot case.]

Fixes: c5b367835cfc ("MIPS: Add support for XPA.")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13124/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
arch/mips/mm/init.c
arch/mips/mm/tlb-r4k.c
arch/mips/mm/tlbex.c